The present invention relates generally to semiconductor wafer fabrication, and more particularly to a method and apparatus for determining temperature of a semiconductor wafer during fabrication thereof.
The manufacture of semiconductor wafers to create semiconductor integrated circuit devices typically involves a sequence of processing steps which fabricate the multi-layer structure generally associated with the integrated circuit devices. Such processing steps may include (1) the deposition of metals, dielectrics, and semiconductor films, (2) the creation of masks by lithography techniques, (3) the doping of semiconductor layers by diffusion or implantation, (4) the polishing of outer layers (e.g. chemical-mechanical polishing), and (5) the etching of layers for selective or blanket material removal.
It should be appreciated that it is generally necessary to maintain relatively precise control of the temperature of a semiconductor wafer during performance of certain of the processing steps associated with manufacture of the wafer. For example, a number of processing steps associated with wafer fabrication involve complex chemical reactions which require the temperature of the semiconductor wafer to be controlled within predetermined specifications. To this end, a number of concepts have heretofore been developed to measure the temperature of a semiconductor wafer during wafer fabrication.
For example, temperature sensors are utilized within a chamber or the like in which the semiconductor wafer is located in order to measure the temperature if the air or other gas within the chamber. The temperature of the semiconductor wafer is then estimated or otherwise derived from the temperature of the air or other gas within the chamber. Moreover, thermocouples have heretofore been secured to a chuck or other type of wafer handling device in order to measure the temperature of the handling device. The temperature of the semiconductor wafer is then estimated or otherwise derived from the temperature of the handling device.
However, such heretofore designed concepts have a number of drawbacks associated therewith. For example, both aforementioned concepts (i.e. use of the temperature sensors within a chamber or thermocouples on a handling device) determine the temperature of the semiconductor wafer indirectly. In particular, both aforementioned concepts require that the temperature of the semiconductor wafer be estimated or otherwise derived from a temperature measurement that is not taken directly from the wafer.
In an attempt to overcome the drawbacks of indirect temperature measurement, a number of concepts have heretofore been developed in an attempt to directly measure the temperature of a semiconductor wafer. For example, optical pyrometers have heretofore been utilized in an attempt to directly measure the temperature of a semiconductor wafer during wafer fabrication. However, use of optical pyrometers has typically not produced consistent measurements due to variations in wafer emissivity.
What is needed therefore is a method and apparatus for determining the temperature of a semiconductor wafer during fabrication thereof which overcomes one or more of the aforementioned drawbacks. What is particularly needed is a method and apparatus for measuring temperature of a semiconductor wafer which measures the temperature of the wafer directly. What is further needed is a method and apparatus for measuring temperature of a semiconductor wafer which measures the temperature of the wafer in-situ.
In accordance with a first embodiment of the present invention, there is provided a method of determining temperature of a semiconductor wafer during wafer fabrication. The method includes the step of providing a response circuit on the semiconductor wafer. The method also includes the step of exciting the response circuit and measuring an output response thereof. Moreover, the method includes the step of determining temperature of the semiconductor wafer based on the output response of the response circuit. The method yet further includes the step of fabricating a circuit layer on said semiconductor wafer. The exciting step is performed contemporaneously with the fabricating step.
In accordance with a second embodiment of the present invention, there is provided an apparatus for determining temperature of a semiconductor wafer during wafer fabrication. The semiconductor wafer has a response circuit. The apparatus includes a signal transceiver for (i) transmitting an interrogation signal which excites the response circuit, and (ii) receiving a response signal generated by the response circuit as a result of excitation thereof. The apparatus also includes a processing unit which is electrically coupled to the signal transceiver. The apparatus also includes a memory device electrically coupled to the processing unit. The memory device has stored therein a plurality of instructions which, when executed by the processing unit, causes the processing unit to (a) operate the signal transceiver to (i) transmit the interrogation signal so as to excite the response circuit during fabrication of the semiconductor wafer, and (ii) measure the response signal generated by the response circuit, and (b) determine temperature of the semiconductor wafer based on the response signal of the response circuit.
In accordance with a third embodiment of the present invention, there is provided a method of determining temperature of a semiconductor wafer during wafer fabrication. The method includes the step of providing a response circuit on the semiconductor wafer. The method also includes the step of transmitting an interrogation signal with a signal transceiver so as to excite the response circuit. The method further includes the step of receiving a response signal which was generated by the response circuit as a result of excitation thereof. In addition, the method includes the step of determining temperature of the semiconductor wafer based on the response signal. Yet further, the method includes the step of fabricating a circuit layer on the semiconductor wafer. Both the transmitting step and the receiving step are performed contemporaneously with the fabricating step.
In accordance with a fourth embodiment of the present invention, there is provided a method of determining temperature of a semiconductor wafer during wafer fabrication. The method includes the step of providing a response circuit on the semiconductor wafer. The method also includes the step of exciting the response circuit and measuring an output response thereof. Moreover, the method includes the step of determining temperature of the semiconductor wafer based on the output response of the response circuit.
It is therefore an object of the present invention to provide a new and useful method of determining temperature of a semiconductor wafer during fabrication thereof.
It is moreover an object of the present invention to provide an improved method of determining temperature of a semiconductor wafer during fabrication thereof.
It is also an object of the present invention to provide a new and useful apparatus for determining temperature of a semiconductor wafer during fabrication thereof.
It is moreover an object of the present invention to provide an improved apparatus for determining temperature of a semiconductor wafer during fabrication thereof.
It is yet another object of the present invention to provide a method and apparatus for determining temperature of a semiconductor wafer during fabrication thereof which measures temperature of the wafer in-situ.
It is moreover an object of the present invention to provide a method and apparatus for determining temperature of a semiconductor wafer during fabrication thereof which is more accurate relative to heretofore designed systems.
It is also an object of the present invention to provide a method and apparatus for determining temperature of a semiconductor wafer during fabrication thereof which does not rely on estimated temperature data.
The above and other objects, features, and advantages of the present invention will become apparent from the following description and the attached drawings.